Woebot for Substance Use Disorders (W-SUDs) is a two-phase NIDA-funded SBIR. Presently, W-SUDs, a novel digital therapeutic, is being evaluated in the Phase I pilot. Phase II will investigate W-SUDs?s efficacy compared to an active control condition. Since the initial award, and across mere months, Covid-19 became a global pandemic, and users worldwide came to Woebot to discuss it and seek help. The company responded by building and deploying Covid- 19 specific programming (W-C19) in March 2020. W-C19 elements have been integrated into W-SUDs; we felt it was timely and appropriate to address users' concerns about the pandemic and demonstrate that Woebot was ?intelligent? to the crisis. Experts expect Covid-19?s direct and indirect impact upon individuals with SUDs to be particularly heavy. These individuals often have physical vulnerabilities, which increase the relative risk of death from Covid-19, and face limited health care access -- fundamentally challenging given often comorbid mental illness. Moreover, high rates of housing insecurity hinders compliance with shelter-in- place and social distancing recommendations, thereby increasing contagion risk. This proposal, with the timely addition of a randomized controlled trial comparing W-SUDs to a waitlist control (WL), expands understanding of W-SUDs? efficacy whilst investigating Covid-19?s impact upon the SUD population. Secular trends of increased substance use are anticipated given Covid-19 stressors (e.g., shelter-in- place, disease concerns, economic strife, under-/unemployment). Hence, the WL condition is essential for testing W-SUDs? efficacy in mitigating these Covid-19 related downstream effects. This proposal extends the parent grant by: (i) adding a randomized controlled evaluation of W-SUDs compared to WL and (ii) investigating potential between group differences on (a) substance use, (b) Covid-19 related components (e.g., social distancing; employment and parental factors), and (c) other SUD treatment engagement. While 20.2 million (8.4%) American adults had a SUD within the past year, only 20% received treatment, given significant treatment access barriers [1]. W-SUDs: (i) is poised to reduce or eliminate common yet significant barriers to traditional SUD treatment; (ii) offers virtual access, optimal for socially distancing and shelter-in-place adherence; (iii) has unconstrained and immediate scale potential; and (iv) delivers content text-based conversation, optimal for engagement. This study offers immediate access to a digital therapeutic in a resource constrained, socially distanced healthcare ecosystem for an already vulnerable and underserved population, likely faced with readily growing psychological challenges.